1. Field of the Invention
The present invention relates a fuel filter, and more particularly, to a fuel filter assembly having an internal air-through passage.
2. Description of Related Art
Generally, in fuel supply in a diesel engine, an injection pump is implemented by injecting fuel in a fuel tank to a combustion chamber of the engine through an injection pump after generating boost pressure with a high-pressure pump for introducing the fuel in the fuel tank through a fuel filter filtering impurities. The fuel filter filters the impurities in the fuel and removes moisture included in the fuel.
In a diesel vehicle, as the setting pressure of the high-pressure pump is in range of approximately 300 bar to 1,600 bar, an ECU (Engine Control Unit) senses an error if the actual pressure of a common rail distributing fuel injection is lower than target pressure by 170 bar to 200 bar or more for one second and controls a fuel amount so that engine RPM is not 2,800 rpm or more in order to protect the high-pressure pump.
As a result, in order to prevent a fault of the fuel filter which is one of causes bringing about such problem, that is, a case that the fuel filter is mounted in the vehicle in a state that air remains in the fuel filter filtering the impurities in the fuel pumped in the fuel tank through the high-pressure pump, an air venting operation of the fuel filter is essentially required in a vehicle assembly line.
However, in case that an inlet of the fuel filter is not filled with the fuel, the air cannot help remaining in the fuel filter and even though the air venting operation is completely carried out, the air is generated in the fuel filter in the course of radical acceleration of fluid in a fault of the fuel itself or lack of a fuel residual quantity in the fuel tank. These phenomena cause pressure drop of the common rail due to the air included in the fuel supplied to the engine, thereby bringing about an acceleration error upon driving.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.